The present invention relates generally to a foldable portable phone (which includes a personal digital cellular (“PDC”) and a personal handy phone system (“PHS”)), and another mobile communication terminal, which are generically referred to as “mobile radio communication apparatus” in the instant application, and more particularly to an internal structure of its hinge part.
Recent widespread mobile radio communication apparatuses, such as PDCs, have roused various demands including operational comfortableness and safety, apparatus's versatility and smaller housing, etc. in addition to mere communications.
In general, there are two types of portable phones, i.e., foldable portable phones and non-foldable, rod-shaped portable phones. The foldable portable phones typically include a movable part that contains a liquid crystal display (“LCD”) screen, a fixed part that contains a ten-key, and a hinge part that connects them foldably. Some foldable portable phones include a free stop function, a one touch opening function, and a safety-improving oil damper (see, for example, Japanese Patent Applications Publications Nos. 2002-344597, 2001-165144, 2001-177266 and 10-65778).
The free stop function is one that maintains an arbitrary angle between the movable part and the fixed part. The one touch opening function is one that automatically opens the movable part when a push button on the fixed part is pressed. The oil damper is such a damper as stores oil in a hinge part's case, and uses oil's viscosity to absorb vibrations when the movable part opens.
A structure has been proposed which prevents damages of the hinge part when the movable part located at an open position receives the load for further opening (see, for example, Japanese Patent Applications Publications Nos. 8-65369 and 2002-295446).
However, these conventional portable phones do not sufficiently satisfy operational comfortableness and safety for calling and non-calling functions.
For example, the ergonomically best angle for calling operations between the movable and fixed parts is between 160° and 170° (referred to as the “best call angle” hereinafter). When an angle between the movable and fixed parts is smaller than the best call angle, a user should manually open the movable part up to the best call angle.
In this respect, Japanese Patent Application Publication No. 2001-165144 discloses, at its paragraph no. 0034, use of a one touch opening function to open an angle at “about 145°” for call. However, a user should actually open the angle to the best call angle, and such twice opening deteriorates the operability and delays starting calling. Similarly, Japanese Patent Application Publication 2001-177266 uses a one touch opening part for opening up to an angle to 20°, and requires subsequent manual opening up to 165°, deteriorating the operability, as disclosed at its paragraph nos. 0014 and 0015.
On the other hand Japanese Patent Applications Publications Nos. 2002-344597 and 10-65778 disclose a one touch opening function for non-stop opening up to the best call angle. However, an opening angle set to the best call angle in a non-stop motion causes a large reaction to be applied at the opening time undesirably and unsafely, such as hopping from a user's hand. In particular, Japanese Patent Application Publication No. 10-65778 provides the movable part with a push button for the one touch opening part, as shown in its FIG. 11, and enables a fixed part to open by its own weight. In view of the fact that the user usually holds the fixed part and enters a telephone number in transmission, the operability deteriorates when a hand holding the movable part changes its position to the fixed part.
Thus, a one touch opening part has not been proposed with excellent operational comfortableness and safety.
In addition, the recently required versatility, such as a camera function and an Internet access function, users need to place, on a desk or another location, a portable phone that inclines by a predetermined open angle, and to view or take a still and motion picture while maintaining the predetermined open angle (or predetermined camera angle). A free stop function has accordingly been required for this versatility.
Thus, recently required high-performance and versatile portable phones need to have a one touch opening function that safely opens the housing up to the best call angle in placing a call, and a free stop function for features other than the call function. As well as these functions, the portable phone should be maintained small. For example, as in Japanese Patent Application Publication No. 2001-165144, a lock/unlock part engaged with a push button for the one touch opening part would undesirably make the housing large when arranged as a separate member at a different position from a forcing part that opens the mobile part from the fixed part.
Those disclosed in Japanese Patent Applications Publications Nos. 8-65369 and 2002-295446 can prevent damages of a hinge in a foldable portable phone that is subject to the excessive load. Nevertheless, the recent portable phones include various functions, such as photographing, games, and accessing to the Internet, and thus are used very frequently. It is thus very convenient for a user who frequently opens and closes the portable phone to prevent hinge's damages and to enable the movable part to rotate around an orthogonal shaft. On the other hand, it is difficult to miniaturize the portable phone as well as enhancing the structural strength of this orthogonal shaft, and thus it is very important to prevent the orthogonal shaft's damages.